For a university project I conducted a little listening test on the new Nero AAC+SBR codec. Other codecs tested were AAC (also Nero codec but without SBR) and Vorbis. The AAC codecs where used at a constant bitrate of 64 kbps and Vorbis at 64 kbps VBR. The results are shown in the follwing graph:

People that conducted the test: JohnV, Ivan Dimkovic, Case, Moneo, superdump and Garf.

Wow! Considering that the AAC encode is CBR and Vorbis is VBR, this is pretty stunning. These will be interesting times, and I hope Xiph.org take a second look at Vorbis once their work has calmed down.

As wise Garf always says, Vorbis has a massive amount of tuning opportunity, so get in there if you have the ability.

I'm also wondering about the speed of the encode... AAC for me has traditionally been a slow encode, is it still the case?

Lol.. You just had to notice that embarrasing detail.. Gotta admit I made one little mistake with the LisztBminor. I'm not gonna start explaining cause you wouldn't believe anyway... Though, that piano sample has very little hf content above 7kHz, so you could in right circumstances after adjusting your default audio settings think that what you hear is noise from distortion and not the hidden reference's high freqs, and think that the 7kHz is actually the hidden reference since there's no know original for comparison and it sounds cleaner... I should have used higher volume on this one, but it was the last sample and I was in hurry...............

EDIT : BTW, interesting test. Thank you for sharing the result Is it possible to download somewhere the BeautySlept AAC+ decoded file ? Just for curiosity ? Or could someone compare it with a WMA9PRO (VBR -q25) encoding, which is very good on harpsichord ?

humm.. quite a difference between fast and HQ setting, interesting. Did you ABX these 2 by accident? Would be interesting to know if "fast" gives out bits more freely to keep up the same quality. Or does it spend 11k more bitrate AND produces lower quality?

But why do they refrain from doing so then? Why is the introduction of SBR came this late? Does SBR bring any disadvantages (like slower decoding in embedded hardware) ?

First, you are right, SBR is an encoder inside an encoder, so decoding is slower.

Other points to consider is break of compatibility with Vorbis 1.0 (not really break, but you would need specific decoders to understand the SBR part, just like MP3/MP3pro); and the patenting issues. SBR algorithms are heavily patented, and they would have to code workarounds to these algorithms.

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Get up-to-date binaries of Lame, AAC, Vorbis and much more at RareWares:http://www.rarewares.org

I think that this setting is optimal for Ogg Vorbis radio. Any settings below sucks, because switching form 44.1khz to 22khz will not cause dropping of kbps by 1/2 and quality is really worse. Same for stereo --> mono.

So IMO main goal for guys from Xiph should be tuning 48kbps 44khz stereo - for radio, and Q5+ for music storing.